Centrifugal machine



Dec. 31, 1929. w. H. BATH CENTR IFUGAL MACHINE Filed m. 10. 1928 Patented Dec. 31 1929 UNITED STATES PATENT OFFICE WILMER H. BATH, OF WEST CONSHOEOCKEN, PENNSYLVANIA, ASSIGNOR TO THE SHARP'LES SPECIALTY COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPO- RATION OF DELAWARE CENTRIFUGAL MACHIN E Application filed October 10, 1928. Serial No. 811,560.

This invention relates to centrifuges and pertains more especially to devicesfor centrifugall separating liquids.

, In such devices, the separated liquids are 5 discharged from a rotating bowl in dispersed condition into stationary annular chambers, the inner edges of the top and bottom walls of which are spaced slightly from the upper surface of the bowl. Rotation of the bowl causes rotation of the air surrounding it due to surface friction between the bowl and the air. The rotation of the air develops centrifugal forces therein which tend to cause a flow of air through the spaces between the bowl and the edges of the chambers and also along the top and bottom walls of the chambers. As a result some of the liquids are carried by the air currents out of the compartment into which they were discharged from the bowl. The liquids carried out of one chamber may be introduced into another chamber or into the casing of the centrifuge, thus causing either intermingling or loss of the separated liquids.

An object of this invention is to counteract the effect of the air currents above described an confine the liquids to the compartments into which they are discharged from the bowl.

Other objects, novel features and advantag'es of this invention will be apparent from the following specification and accompanying drawings wherein:

ig. 1 is a vertical section of a centrifuge 5 embodying the invention and Fig. 2 is a similar view of a modified embodiment of the invention.

The casing of the device is designated by the reference character 10, and within this casing is rotatably mounted a bowl 11. This bowl is provided with a head 12 having passageways 13 and 14 through which the separated liquids are discharged in dispersed condition. The head is also provided with a neck 15 by means of which the bowl 11 is supported and rotated by suitable driving means (not shown).

A cover 16 surrounds the bowl 11 and is supported by the casing 10.' A second cover 17 is supported from the first cover 16 and forms therewith a chamber into which liquid 18 discharged from the bowl 11 through the passageway 13. A lid 18 is supported by the cover 17 and forms therewith a chamber into which liquids are discharged from the bowl 11 through the passageway 14. The covers 16 and 17 are provided respectively with spouts 19 and 20 by means of which the liquids discharged into the chambers may be drained therefrom.

the air in contact therewithand the rate of rotation is substantially proportional to the diameter of the portion of the bowl in contact therewith.' Where the rate'of rotating of the air is greatest the air will have the greatest centrifugal force and vice versa. The centrifugal force in the casing will therefore be greater than that in the chamber forced b the covers 16 and 17 which, in turn, wil be greater than the centrifugal force developed in the chamber formed by the cover 17 and lid 18. As a result there will be a tendency for air to flow from the upper chamber into the lower chamber and from the latter into the casing. There may bea flow of air in or out of either spout 19 or 20 according to the amount of air which passes through-the annular spaces. The air in contact with the surface of the bowl will have a greater angular velocity than the air in contact with the top and bottom walls of the chambers. Therefore, the air in contact with the top and bottom walls will have less centrifugal force than the air midway therebetween and accordingly the rotating air will move inwardly in a spiral direction along such walls and move outwardly in a spiral direction intermediate the walls.

The currents of air thus produced by rotation of the bowl tend'to carry liquid which has been deposited on the bottom and top walls of the chambers toward the inner edges of the covers from which it may drop or be blown downwardly out of the chamber by the above described currents. As a result, liquids discharged into one of the chambers may be carried out therefrom into another chamber or into the casing of the centrifuge,

Rotation of the bowl 11 causes rotation of thus causing either inter-mingling or loss of the separated liquids.

According to this invention the flow of air from the lower chamber to the casing 10 is prevented by supporting an inverted frustoconical collar 21 at the inner edge of the cover 16 and providing a pipe 22 leading from the exterior of the machine through the collar to. the space between the collar and the bowl. The air rotating in the space between the collar and the bowl develops a centrifugal force causing it to have an outward pressure. The outward upward slope of the collar 21 causes such pressure to produce upward flow of air along the inner surface of the collar and outwardly across the top edge thereof into the chamber. The pipe 22 supplies suflicient air to the space between the bowl and the collar to compensate any leakage of air from the casing 10 and to provide an .upward current of air toward the top edge of the collar.

The flow of air in the space between the bowl and the collar is therefore directed upwardly and outwardly across the top edge of the collar. This current of air tends to carry outwardly of the chamber any liquid which may have collected on the top edge of the V collar as well as the atomized liquid in the vicinity thereof. The current of air thus produced effectively prevents loss of liquid from the lower chamber to the casing. Referrin now to Fig. 2, the various ele ments of t e centrifugal device are designated by the same reference characters as used in connection with Fig. 1. In the embodi-- ment disclosed in Fig. 2, the cover 16 is constructed to provide an annular passageway 23 communicating with the central portion of the, frusto-conical collar 21. This is accomplished b making the cover 16 in two sec-.

tions, eac of which is soldered orotherwise connected to the frusto-conical collar 21 which is cut away between such sections to form'a series of slots 24. The annular passageway 23 permits the supply of air to the space between the collar and the bowl so that the operation of theembodiment disclosed in Fig. 2. is the same as the operation of the embodiment disclosed in Fig. 1. In both embodiments the upward flow of air in the space between the bowl and the collar prevents the loss of liquid from the lower chamber to the casing.

The primary eflect of this invention is to prevent leakage of liquid from the lower chamber into the casing 10. However, the upward current of air produced according to this invention may be made suflicient to create a balance of conditions between the lower and -upper chambers so that there is no current of leakage from the upper chamber to the lower fix/41,895

chamber. Furthermore, if leakage one way is very objectionable but in the other way is not objectionable, the passageways 22 and 23 may be made of such capacity that the upward pressure produced in the space between the bowl and the collar will result in preventing leakage in the objectionable direction, while permitting it in the unobjectionable direction.

Although in the embodiments of the invention specifically disclosed herein, the collar 21 is supported by the cover 16 and prevents loss from the lower chamber to the casing, it is apparent that it is within the contemplation of this, invention that the collar be supported by the cover 17 for the purpose of preventing loss from the upper to the lowerchamber. The invention can be made use of wherever it is desired to prevent loss from a discharge chamber of a centrifugal machine. v 7

It is, of course, understood that various structural modifications may be made in the above disclosure without in any way departing from the spirit of the invention as de-, fined in the appended claims.

' I. claim 1. In a centrifugal machine, a casing, a

' bowl rotatably mounted therein, covers forming chambers for receiving liquids discharged from said bowl, an inverted frustoconical collar carried by one of said covers and a vent to atmosphere from the space between said bowl and collar.

3. In a centrifugal machine, a casing, a bowl rotatably mounted therein, covers forming chambers for receiving liquids discharged from said bowl, an inverted frusto-conical collar carried by one of said covers and a pipe leading to the space between the collar and the bowl.

4. In a centrifugal machine, a casing, a bowl rotatably mounted therein, covers forming chambers for receiving liquids discharged from said bowl, an inverted frusto-conical 

